Relay



1,493,870 May 10 1924 c. s. SNAVEI .Y

RELAY Filed May 13, 191

INVENTOR Patented May 13, 1924.

UNITED STATES PATENT OFFICE.

CLARENCE S. SNAVELY, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RELAY.

1' '0 all whom it may concern: W,

Be it known that I, CLARENCE S. SNAVELY, a citizen of the United States, residing at Pittsburgh, in the county'of Allegheny and State of Pennsylvania, have invented certain. new and. useful Improvements in Relays, of which the following is a specification. I

My invention relates to relays, and particularly to means for mounting the contact fingers employed in relays. More specifically the invention relates to means for mounting that type of contact finger which comprises a relatively rigid part attached to the contact operating member and a fiexi ble part which bends when the contact is closed with pressure.

One feature oi my invention is the provision of means for attaching the rigid part of the contactfinger to the operating mem her. which means will rigidly unite the two under ordinary operating conditions, but will yield in the event of unusual stress.

The present application is in part a continuation of my co-pending application filed Dec. 15, 1916, Serial No. 137,263, now Patent No. 1,309,108, issued July 8, 1913, for mounting for contact finger and method of adjusting the same. i

I will describe two forms of mounting means embodying my invention, and will then point out the novel teaturesthereot in claims.

In the accompanying drawings, Fig. 1 is a view showing in side elevation a portion of a relay including one form of contact finger and one form of mounting means therefor embodying my invention. Fig. 1 is a view showing the mounting means shown in Fig. 1, but on a larger scale and partly in section. Fig. 2 is a view showing a modified form of mounting means also embodying my invention.

Similar reference characters refer to similar parts in each of the views.

Referring first to Fig.1. thereference character 5 designates the supporting plate of a relay, which plate carries an. electromagnet M having a pole piece C. Attached to this pole piece is a bracket 13, in which the armature A of the relay is pivotally mounted, so that this armature is attracted toward the pole piece when the relay is energized. The armature A carries a contact 1919. Serial no. 296,817.

finger F comprising a relatively rigid part or bar 12 and a flexible part or tip 13, which tip is arranged to engage with a fixed contact 1st carried by the plate The bar 12 of the contact finger is attached to the armature A by means which I will now describe. Interposed between the bar 12 and the armature are two studs 18 of insulating material, each of which studs is attached to the armature by a screw 22 passing into a threaded hole in the armature, ,thehead of the screw being imbedded in the stud as shown in Fig. 1. Each stud 18 carries a second screw 17 the head of which is likewise imbedded in the stud and the shank 01 which projects downwardly through a. suitable hole in the contact bar 12. The bar 12 is held normally in engagement with the studs 18 by means of springs 21, one end of each spring resting against the bar and the other end against a washer 20, the washer being held in place by a nut 19 on the outer end of the screw. The action of the springs 21 is sufiicient to hold the bar 12 rigidly in engagement with the studs 18 during ordinary operation of the contact, but these springs will yield to allow the bar to leave the studs in the event of unusual stress on the bar.

,Referring now to Fig. 2, I have here shown an adjustable weight as a substitute for the springs shown in Fig. 1. In Fig. 2 the relatively rigid part or bar 12 of the contact finger is pivotally mounted at 9 in a stud 18 of insulating material carried by the ari'nature This bar 12 also rests normally against a screw 10 which is mounted in another stud 18 of insulating material likewise carried by the armature A. The bar 12" is normally held in engagement with the end of this screw 10 by a weight 11, which is mounted on the bar and is adjustable thereon by virtue of screw threads on the outer end of the bar. The weight is held in adjusted position on the bar by a lock nut 11 The torque exerted by the weight 11 is such that during normal operation the bar 12 is held in engagement with the screw 10, but that in the event of unusual stress on the contact tip 13 the bar 12 will swing in clockwise direction around its pivotal point 9.

It will be noted that the screw 10 can be adjusted to vary the normal pressure between the contact finger F and the fixed contact ll.

Referring now to both of the views, it is of course understood that the contact is so adjusted that when the armature A is at tracted by the magnet M, the contact tip 13 or l3 engages the fixed contact member 14 before the armature fully closes, and that during the remainder of the movement of the armature the tip bends so that its outer edge slides along the member 14. As long as this bending is no greater than the normal amount, the bar 12 or 12 will be held rigidly with respect to armature A so that the proper amount of pressure will be developed between the tip and the fixed member 14. But it for any reason, such as distortion of some part of the contact finger, the armature should attempt to cause more than the normal amount of bending of the contact tip, the bar 12 or 12 will. move with respect to the armature and so will prevent permanent distortion of any part of the contact finger.

Considering particularly the structure shown in Fig. 2, it will be observed that the contact finger cannot develop a pressure greater than that for which the weight 11 has been adjusted; alter this pressure has been reached the bar 12 will merely swing on its pivot pin 9. This feature is of particular advantage in a relay comprising a plurality of contact fingers mounted on a single armature, "for the following reasons: A contact finger which has become bent or distorted cannot prevent the other contacts from closing because the distorted finger will swing on its pivot after it has devel oped its full pressure and so will permit the other contacts to close. It is not necessary for the armature to do an excessive amount of work in compressing the distorted fingers so as to close the remaining fingers, because the distorted finger will swing on its pivot as soon as it has developed its maximum pressure, and will then require no further work on its own account while the armature is compressing the remaining fingers to their full pressure. Thus this structure will serve to equally distribute the pressure over the individual contact fingers, even though some or all of the fingers may be out of alignment or adjustment.

The foregoing advantages of the structure shown in Fig. 2 are also inherent in the structure shown in Fig. 1, but to a somewhat less degree because the pressure exerted by springs 21 on the contact bar 12 increases as these springs are compressed.

Although I have herein shown and described only two forms of'contact mountings embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a contact operating member, a fixed contact, a contact finger coacting with said fixed contact and comprising a relatively rigid part and a flexible part which bends when the contact is closed with pressure, and means for yieldingly attaching the rigid part of said finger to the operating member with such force as to unite the two parts rigidly under ordinary operating conditions but to yield in the event of unusual stress.

2. In combination, a contact operating member, a fixed contact, a contact finger coacting with said fixed contact and comprising a relatively rigid. part pivotally mounted on said operating member and a flexible part which bends when the contact is closed with pressure, a stop on said operating member, and a weight attached to the rigid part of said contact finger for biasing the finger towards said stop, said weight being adjusted to hold the finger rigidly against the stop under ordinary operating conditions but to allow the finger to swing on its pivot in the event of unusual stress.

3. In combination, a contact operating member, av fixed contact, a contact finger coacting with said fixed contact and comprising a relatively rigid part pivotally mounted on said operating member and a flexible part which bends when the contact is closed with pressure, an adjustable stop on said operating member, and a weight attached to the rigid part of said contact finger for biasing the finger towards said stop, said weight being adjusted to hold the finger rigidly against the stop under ordinary operating conditions but to allow the finger to swing on its pivot in the event of unusual stress.

In testimony whereof I afiix my signature in presenc of two witnesses.

CLARENCE S. SNAVELY.

Witnesses A. HERMAN I/VEGNER, E. P. CRUM. 

